1. Field of the Invention
The invention is related to guidewires used for the insertion of catheters into the vascular system as a method of treating coronary arterial vascular blockage.
2. Description of the Prior Art
As a treatment technique for removing blockages in the vascular system, particularly those which affect the blood supply to the heart, guidewires of very fine diameter are inserted directly into the system from outside the patient and manipulated or steered by the physician or practitioner through the system to the blockage by fluoroscopic observation. Since the various arteries through which the wire must pass are sinuous or irregular in shape and intersect and connect with other vessels at various and sometimes sharp angles, maneuvering the wire to the position of concern is a delicate task. A plurality of guidewire type devices designed for this purpose exist in the prior art.
Each is a novel approach to the problem of providing the user with sufficient control to transverse the vascular system in a speedy and careful manner.
For example, U.S. Pat. Nos. 4,545,390, Leary, and 3,789,841, Antoshkiw, both show distal tips formed of helically wound springs surrounding fixed tapered cores. U.S. Pat. No. 3,631,848, Muller, describes an axially movable distal tip extension tube of relatively short length.
A coil tip with tapered face edges which will curve toward the taper when pulled upon by an internal control wire is disclosed in U.S. Pat. Nos. 3,452,740, and 3,452,742, both to Muller. U.S. Pat. No. 4,650,467, Bonello shows a similar arrangement for inclining the tip by retraction of a control wire affixed thereto.
Additionally, U.S. Pat. No. 3,528,406, Jeckel et al. teaches the use of a fixed core wire having a reduced diameter in the spring tip portion of the wire. U.S. Pat. No. 3,625,200, Muller, discloses a curvable tip comprising solid cylindrical links engaging each other with ball and socket joints each of which is manipulatable by a fine core wire. Finally, U.S. Pat. No. 4,573,470, Samson shows a curved tip which is rotated in its entirety by rotating a core wire at the control handle.
The present invention is an improved guidewire which allows the user to vary the stiffness of the wire and vary the curvature of the tip from outside the patient during the transport and manipulation process.